Add my 'gibiansky' style, a test suite, and ability to parse modules

This PR achieves (roughly) the following things:

- Add a new style for me, `gibiansky`
- Add a test suite (`Spec.hs` and `tests`)
- Clean up some of the older functions (add comments, mostly)
- Fix some things `hlint` was complaining about
- Add a few instances of `Pretty` and some helper functions (`getColumn`)